In 1843, Peter H. Burnett, living then in Clay County, Missouri, determined to move to Oregon. He was induced to do this by the Congressional report of Senator Appleton on that country. Senator Linn, of Missouri, had introduced into Congress a bill granting a settler six hundred and forty acres of land for himself and one hundred and sixty acres for each of his children. Under that act, should it pass, he would be entitled to sixteen hundred acres of land.

Dr. Whitman, the missionary, was then on the western border of Missouri. Burnett and others forming the company were in communication with him. On the 18th of May the emigrants held a meeting to perfect arrangements for the journey and to see Dr. Whitman. This meeting appointed a committee of seven to make an inspection of the wagons intended for the trip. A committee of five was selected to formulate rules for the journey. Dr. Whitman was also present at a meeting held on the 20th of May, when the rules were adopted. John Grant was hired to act as guide as far as Fort Hall. The rendezvous was about fifteen miles east of Elm Grove, which was reached on the 22d of May—the day of the starting. Two elm trees and some dogwood brush constituted the grove. The larger elm had been stripped of its branches for wood by previous caravans. The party crossed the Wakarusa on the 24th, letting the wagons down the steep banks by ropes. It is not known just where the Kansas River, reached on the 26th, was crossed, but it was probably at the Uniontown Ford, but possibly at the mouth of the Big Blue. It required until the 31st to complete the crossing for all the party. There were met Fathers De Smet and De Vos, coming from missionary labors among the Flathead Indians. The next day the organization of the company was completed by the election of Burnett as Captain and J. W. Nesmith as Orderly Sergeant; also the selection of a council of nine members. A war party of Kansas and Osage Indians was encountered on the 6th of June. This party had gone out against the Pawnees, and had taken one scalp, which was exhibited, showing the ears with the wampum still in them. The party followed up the Big Blue more closely than did later caravans, making its last encampment on that stream on the 17th—already beyond the boundary of what was to become Kansas.